News
| August 9, 2000

How drug-resistant microorganisms affect nursing

Although antibiotics have improved the mortality and morbidity associated with infectious disease, antibiotic mismanagement has created drug-resistant microorganisms, which are present in the environment outside the hospital. In the hospital, drug-resistant microorganisms require Contact Isolation, a transmission-based isolation recommended by the Centers for Disease Control and Prevention. The nurse's role in preventing the spread of drug-resistant microorganisms includes using appropriate infection control and isolation guidelines (especially handwashing), working with other health care workers to maintain appropriate infection control standards at all times, and teaching patients and families about infection control and antibiotic management.

The first antibiotics were used in the 1930s. During World War II, antibiotics worked "wonders," preventing deaths from bacterial wound infections. In the decades after the war, infections with high mortality rates such as tuberculosis, pneumococcal meningitis, and pneumonia became more treatable.

Antibiotics are chemical compounds that work by interfering with crucial processes within bacteria to cause cell damage or death. Some antibiotics work by inhibiting the ability of bacteria to synthesize protein, that is to perform normal cellular functions or reproduce. Other antibiotics disrupt the bacterial cell membrane causing the cell to disintegrate (see Table 1).

Development of Drug Resistant Microorganisms
Drug resistance is inevitable because of natural evolution. Bacteria reproduce quickly, allowing generations of genetic changes to occur in a short time. Bacteria that have adapted include:

Methicillin-resistant Staphylococcus Aureus (MRSA)

Vancomycin-resistant Enterococcus (VRE)

Penicillin-resistant Pneumococcus

Multi-resistant Pseudomonas Aeruginosa

Multidrug-resistant Mycobacterium Tuberculosis

When antibiotics are used, some hardy microorganisms may survive (Sheff, 1999). This is antibiotic resistance in a single organism or generation. As these bacteria reproduce, they pass this antibiotic resistance to subsequent generations. Stronger antibiotics are then used, which can escalate the cycle of antibiotic resistance. This is more likely to occur when antibiotics are stopped prematurely (before all bacteria are killed), or when given empirically (for example, using sulfa for a urinary tract infection (UTI) because UTI is most often caused by Escherichia coli). Penicillin-resistant pneumococcus, and multidrug-resistant tuberculosis are examples of this problem.

Some microorganisms share genetic material (DNA) with other bacteria that carry bacterial resistance. MRSA develops in this way. Epidemiologists now fear that a methicillin-resistant VRE will develop by this same transformation process.

Patients have contributed to drug resistance - the development of drug-resistant organisms - by prematurely stopping antibiotics, not taking the complete antibiotic prescription ("saving it for the next time"), stopping antibiotics as soon as they feel better rather than taking a full course, and sharing their antibiotics with family members (these anitbiotics may not kill the infecting organism because they are not appropriate for the organism involved or they are not the correct dose).

According to Morris et al. (1995), health care workers' actions that play a part in the development of drug-resistant organisms include not washing hands for at least 15 seconds before and after patient contact, not maintaining appropriate isolation, mishandling contaminated material, not using appropriate cleaning or disinfecting procedures, and not restricting duty when infectious.

The Problem
The human body is a virtual microorganism warehouse. Bacteria, resident on the skin and in the gastrointestinal tract, are essential to our health. Therefore, a positive culture can mean a microorganism is present, even without an infection (Table 2).

Infection can occur when a microorganism moves to a location where it is not normally found. For example E. coli from the bowel causes a urinary tract infection. Or there could be a breakdown in the body's natural defense mechanisms (for example, a surgical incision, other wound, or immunosuppression) (Belmatoug et al., 1996).

This means some people are more susceptible to infection (see Table 3). These same people are often patients in a clinic or hospital. Infection is still the "second most common complication of orthopedic implant surgery" (DeBaun, 1998, p. 671).

Source: DeBaun, 1998; Norman et al.,1997

Postoperative wound infections may be the result of contamination of the surgical wound during the procedure, or migration of an infection from another infection site. It could also be a reactivation of an infection that occurred previously (Debaun, 1998). A common site of hospital-acquired infection is the urinary tract secondary to a procedure or catheterization.

Both patients and health care workers can be colonized with drug-resistant microorganisms. Environmental cultures have shown VRE and MRSA on linens as well as hard surfaces such as bedrails, bedside stands, and medical devices (Duerden et al., 1997; Morris et al., 1995 )

Methicillin-Resistant Staphylococcus Aureus (MRSA)
Staphylococci reside on the skin and mucous membranes including the linings of the respiratory, intestinal, and genitourinary tracts. Intact skin is adequate to prevent infection by staphylococci. Any break in skin integrity may lead to staphylococcal infection. Staphylococcus aureus becomes pathogenic in surgical wounds.

Infection may result from inadequate skin preparation or contamination of the surgical site by bacteria on hands or adjacent skin. Overuse or misuse of antibiotics, particularly methicillin, to treat wound cultures that grow Staphylococcus aureus have contributed to the development of MRSA.

Vancomycin-Resistant Enterococcus (VRE)
Enterococci, previously called group D strep, are resident in the gastrointestinal tract and female genital tract. Skin surfaces may easily be contaminated by enterococci due to poor hygiene. Overuse of vancomycin to treat other infections may have caused the development of VRE.

Approaches to Combat Drug Resistance
The "war" against drug resistance is being fought on two fronts. First, guidelines are being developed in most health care settings to manage the use of antibiotics. Second, infection control measures are being used to confine the spread of microorganisms.

Guidelines for Use of Antibiotics
Most health care facilities have a Pharmacy and Therapeutics Committee, a medical-staff committee that develops guidelines for drug use. Some antibiotic guidelines that may be in effect where you work include:

monitoring of antibiotic therapy; checking peak and trough levels

restricting the use of certain antibiotics empirically for preoperative prophylaxis, i.e., vancomycin

reviewing antibiotic use based on cultures

recommending use of narrow-spectrum antibiotics until culture reports return

suggesting combination approaches to antibiotic therapy

Infection Control Measures
The Centers for Disease Control and Prevention (CDC) has published guidelines for a two-tiered approach to isolation. The first tier, Standard Precautions, assumes that all body substances may be infectious and recommends barrier precautions when handling body substances. The second tier, Transmission-based Precautions, uses personal protective equipment (PPE) based on the mode of transmission of the infectious organism.

Adapted from Guidelines for Isolation Precautions in Hospitals, CDC, 1996.

Handwashing for at least 15 seconds with antibacterial soap is the single most effective method for maintaining this type of isolation. In fact, a 30-second antiseptic wash is necessary to completely remove VRE from the hands (Noskin et al., 1995).

Guideline for Infection Control in Health Care Personnel (CDC, 1998) makes recommendations about work restrictions to prevent transmission of infection to and from personnel. Some of these restrictions are obvious because they involve a known communicable disease such as mumps, measles, or tuberculosis. The infections that may require work restrictions that are not as obvious are those passed by direct contact (see Table 5). Work restrictions are particularly important in areas where "at risk" patients are found.

Adapted from Guidelines for Infection Control in Health Care Personnel, CDC, 1998.

Guidelines for Isolation Precautions in Hospitals (CDC, 1996) lists management recommendations for the patient care environment (see Table 6). The recommendations are very general, allowing each facility to specify the actual procedures and cleaning/disinfecting agents to be used.

Adapted from Guidelines for Isolation Precautions in Hospitals, CDC, 1996.

There are currently no national guidelines for surgical skin prep. However, most surgeons use an antibacterial skin cleanser preoperatively. Risk factors for surgical site infection may include razor shaves, low abdominal site, use of prosthesis, no prophylactic antibiotics, and tissue trauma (DeBaun, 1998). Dipilatories and electric clippers cause fewer skin disruptions than razors, thereby decreasing the risk of colonization of the operative area. (Hamilton & Lone, 1977).

reporting patients with signs of infection to the Infection Control Practitioner promptly

reporting infections that may cause work restrictions

using extra care if you have an open wound

appropriate dressing/wound cover

adequate personal protective equipment

washing with antibacterial soap for a full 30 seconds

Specific actions needed for preventing the spread of drug-resistant microorganisms include encouraging the use of pneumococcal vaccination, teaching families about Contact Isolation and handwashing, and communicating the need for special handling or precautions to other departments who care for patients with drug-resistant microorganisms.

The sidebar scenario (above) demonstrates how drug-resistant microorganisms may be spread within a health care facility. These same organisms may live long enough on a uniform or shoes to contaminate the health care worker's car, home, and places the worker stops on the way home. This colonization (Table 2) of the environment may result in healthy people becoming colonized with drug-resistant microorganisms. Then, when the body's immune system is compromised, a drug-resistant infection may develop.

Conclusions
Does this mean that nurses should wear shoe covers at all times? Or change clothes and shower before leaving work? These steps should not be necessary if guidelines are followed.

Nurses MUST use infection control measures to prevent the development and spread of drug-resistant microorganisms. That means Standard Precautions for everyone. But most of all, that means handwashing before and after all patient contact. Most hospitals are using antibacterial soap in all patient care areas. Handwashing for 15 to 30 seconds will do the most to prevent the development and spread of all nosocomial infections. Effective methods for infection control include both handwashing and use of personal protective equipment.

Nurses must also work with other health care workers - both professional and nonprofessional - to maintain appropriate infection control standards at all times. Infection control is enhanced by appropriate use of antibiotics, availability of adequate equipment and supplies to maintain precautions, and communication with others about the presence of infections, particularly with drug-resistant microorganisms.